Serotonin (5-HT)-related symptoms and fluoxetine in geriatric depression

We evaluated 5-HT-dependent symptoms as predictors of response to Fluoxetin e in late life depression (LLD). Thirty-six depressed in- and outpatients a ged 65 years or more, diagnosed according to DSM-III-R criteria, were evalu ated using the 21-item Hamilton rating scale for depression (HRSD). After 6 weeks of Fluoxetine treatment (20-40 mg/day), patients were classified as "responders" (n = 22, > 50 % decrease in the HRSD total score) and "non res ponders" (n = 14). For the HRSD, both overall scoring and the scores for sp ecific symptomatologic clusters were analyzed in a statistical model compri sing the stepwise regression analysis and the exploratory factor analysis w ith varimax rotation. Among responders, five variables (thought disturbance , suicide, sleep disturbance, agitation, and obsessive-compulsive symptoms) accounted for almost 80 % of the total variability. Furthermore, factor an alysis extrected two factors: the first was dominated by the suicide, sleep disturbance, and agitation clusters; the second weighted on thought distur bance and obsessive-compulsive symptoms. As in the younger population, symp toms related to a 5-HT dysfunction appear to act as predictors of the favor able response to Fluoxetine in geriatric depression as well.